Make ’Em Sweat — The Biology of Body Odor

Everyone’s got body odor — even those who think their (pits) don’t stink. But not all odors are repulsive or the kind easy to get rid of with a stick of Degree. The biology behind body odor is pretty tricky, but it's partially based on three types of glands that contribute to odors.Sweat glands exist all over the body and kick into gear when we exercise, become overheated, or feel anxious. Sebaceous glands are also found throughout the body and only start producing their oily liquid during puberty. Apocrine glands, located mostly in the armpit and pubic regions, also start acting up around adolescence and can cause some serious stink. Steroids in apocrine secretions, especially the ones that come from the armpit, are some of the biggest culprits behind adult B.O. But — here's a real shocker — sweat and other secretions don’t actually smell. Sweat, sebaceous, and apocrine glands secrete volatile organic compounds, and odors arise when these "VOCs" interact with bacteria on the skin, in hair follicles, and in the mouth.

Genetics can influence our ability to detect certain odors, too. As anyone who’s walked into a boys’ locker room can guess, women are generally more sensitive to body odor than men are. Some researchers suggest this is because throughout history, women have had to be pickier about choosing the right mate. And people react completely differently to certain odors because of their unique DNA. Take androstenone, one of the steroids in human sweat and urine. Some people say it smells like vanilla, others find it appeals to their nostrils as much as sweat or urine, and some can’t smell it at all.

B.O. You Can Be — What Body Odor Communicates

But body odor can reveal more than just whether someone used deodorant today. Want to know if a new pal’s outgoing, neurotic, or bold? Try taking a whiff of his/her armpit. (Proceed with caution.) There’s some evidence people can predict certain personality traits just by sniffing odor samples. Body odor also has a lot to do with romantic attraction — beyond the fact that it’s a good idea to deodorize before a date. Sweat, skin oils, and other secretions release pheromones, molecules that help animals communicate. In humans, pheromones can convey important information about who’s a potential match — no OkCupid profile required.

Back in the caveman days, our nostrils may have also helped us avoid incest. It’s still not clear whether family members can recognize each other’s smells, and people might only develop the ability once they hit adulthood Family scents: developmental changes in the perception of kin body odor? Ferdenzi, C., Schaal, B., Roberts, S.C. Evolutionary Psychology and Behavioral Ecology Research Group, University of Liverpool, Liverpool, UK. Journal of Chemical Ecology 2010;36(8):847-54.. Some research suggests humans are especially skilled at sniffing out same-sex siblings Possible olfaction-based mechanisms in human kin recognition and inbreeding avoidance. Weisfeld, G.E., Czilli, T., Phillips, K.A. Department of Psychology, Wayne State University, Detroit, MI. Journal of Experimental Child Psychology 2003;85(3):279-95.. But there are certain situations when body odor indicates a serious health issue.

Battling B.O. — Body Odor Disorders

In most healthy adults, body odor isn’t a problem that deodorant and a regular shower routine can’t take care of (although some people might smell just fine going au natural). But there are certain foods, habits, and medical conditions that can have friends and coworkers wearing face masks.Foods like garlic and curry can cause some smelly situations, since they contain chemicals that our glands excrete onto the skin. And burger-lovers beware: Some women think men who eat a lot of red meat smell worse than those who take their meals with a little less beef The effect of meat consumption on body odor attractiveness. Havlicek, L, Lenochova, P. Department of Anthropology, Faculty of Humanities, Charles University, Prague, Czech Republic. Chemical Senses 2006;31(8):747-52..

There are a few easy ways to combat B.O: Bathe regularly, wear fresh clothes, and apply deodorant daily. (Some people say antiperspirants pose health risks, but the research is unclear.) And don’t forget to wash and dry feet and wear clean socks. B.O., be gone!